The present invention relates to a graphic arts film or a process film. More particularly, it is concerned with a graphic arts film or a process film with toner image formed on a light-transmitting base sheet having a toner-adhesive and ink-repellant, transparent coating layer formed thereon.
There are known graphic arts films comprising a transparent base sheet and a light sensitive compound which eventually leads to an increase in the optical density of image and which has been applied onto the base sheet in the form of a uniform or non-uniform layer. For example, there are known (a) a panchromatic black-and-white film prepared by dispersing fine particles consisting mainly of fine silver halide particles in gelatin and applying the resultant dispersion onto a film, (b) a diazo film prepared by mixing a light sensitive diazo-compound as a main component intimately with resins and applying the resultant composition onto a film, and (c) a photo-polymer film prepared by applying a photo-polymerizable monomer or photo-polymer, a colored pigment and other resin onto a film uniformly with respect to the plane of the film and uniformly or laminatedly in the direction perpendicular to the film surface. All of these films have superior points in performance, cost, etc. and have long been practically used or are being put to practical use.
It has also been proposed to form a toner image on, for example, a transparent film or translucent paper by electrophotography to obtain a graphic arts film or a positive film for line work.
However, those conventional films are not always free from problem. For example, in the case of the silver salt film, due to the recent decrease of silver resources, the cost of silver has remarkably increased and is greatly affecting the manufacturing cost of the film. In point of performance, moreover, the image density may lower in retouching (dot-etching) or in the case of first preparing a negative film from a positive film and further preparing a positive film using the negative film prepared. Other problems involve the presence of pin-holes, impossibility of a perfect daylight processing, and a long time required for development, fixing and drying.
In the case of the diazo film, it is advantageous in point of cost, but in point of performance it involves inconveniences such as an insufficient optical density and inapplicableness of retouching of imaginary part by dot-etching or the like, and therefore its application range is limited. Furthermore, in the case of the coated film comprising a photopolymerizable material and a colored pigment, its full-scale practical application involves problems such as the difficulty of retouching of imaginary part and an insufficient shelf life of the film.
In the case of using electrophotography, moreover, not only the density of toner image formed on the film is insufficient and non-uniform, but also, for example when retouching the image toner by dissolution, the optical density of the toner image further lowers to the extent it is difficult to use the film as a graphic arts film.
The present invention provides an imaged film free from the above-mentioned problems.